The present invention relates to a technology for controlling an optical disk memory device and an optical disk memory system, and more particularly to a technology effectively applicable to, for example, a backup technique utilizing a medium exchangeable memory device.
As known in the art, in an information processing system such as personal computer or work station, a memory device of large capacity, for example, a streaming tape device such as cassette streamer or DAT (digital audio tape recorder) is used as a backup device for large-capacity data in a memory device such as hard disk device.
On the other hand, the storage capacity of the medium exchangeable memory device represented by, for example, a DVD-RAM device has been improved remarkably in recent years and a device of this type capable of realizing a storage capacity per unit portable recording medium which is comparable to that of the aforementioned steaming tape device or DAT has shown itself. Generally, the DVD-RAM device can afford to access recording media of different capacities or read-only media such as DVD-ROM and CD-ROM.
Then, it is conceivable to use the medium exchangeable memory device of large capacity represented by, for example, the DVD-RAM as a backup device. In backup utility software attached to, for example, a general-purpose operating system (OS), however, its write destination is fixed to a device for backup, for example, the streaming tape device such as cassette streamer or DAT. The format of the backup dedicated device differs from the standard file format of the OS and therefore, when the medium exchangeable memory device is allocated as it is to the backup memory device, it cannot be used in common to an OS file system to raise a problem that usability of the large-capacity medium exchangeable memory device is degraded.
Further, in a medium exchangeable memory device having a plurality of recording media housed in, for example, a magazine and having the function to replace the magazine, it is necessary to consider whether a recording medium of magazine serving as a data backup destination is mounted.
Besides, consideration must be taken as to whether a different kind of medium other than that for backup coexists in the recording device.
An object of the present invention is to provide, in a medium exchangeable memory device having the function to replace a plurality of portable recording media housed in a magazine, a technology for executing smooth data backup without being affected by the kind and state of the plurality of portable recording media in the magazine.
Another object of the invention is to provide a technology for improving usability by using the medium exchangeable memory device in common to data backup and an OS file system.
According to the present invention to solve the above objects, in a medium exchangeable memory device having a plurality of slots for housing portable optical memory media and being operative to select a desired optical recording medium to read/write data, a recording medium held in a slot is decided as to whether it is permitted to be written and when writing is not permitted, writing to a recording medium in another slot is carried out. Further, in a medium exchangeable memory device having a detachable magazine provided with a plurality of slots, when a recording medium in a slot is not permitted to be written, writing to a recording medium held in another slot of the magazine is carried out.
Further, according to the invention, an identification number is assigned to a unit of recording medium or slot holding the recording medium and it is decided whether write of data to a recording medium assigned with a designated identification number or a recording medium of a slot assigned with the designated identification number is permissible. If writing is impermissible, data is written to a recording medium assigned with an identification number which is next as viewed in the order of increasing of identification number or a recording medium of a slot assigned with the next identification number.
Determination as to whether the recording medium is permitted to be written is carried out through the following method. More particularly, (1) it is decided whether a recording medium is housed in a slot having a designated identification number, (2) it is decided whether the recording medium is a read-only medium such as DVD-ROM or CD-ROM, and (3) it is decided whether the recording medium is formatted to another file system.
Further, in a medium exchangeable memory device having a plurality of recording media housed in, for example, a magazine and having the function to replace the magazine, it is decided whether write of data to a recording medium assigned with a designated identification number or a recording medium in a slot assigned with the designated identification number is permissible and when writing is impermissible, writing to a recording medium in another magazine is carried out.